Pls refer to these step to solve the wrong password issue.
1) If you doesn't change the User Name and the Password on NVR box.
The User name is 'admin', no password (you don't need input anything)
2)For changing the password on NVR box.
Right click the mouse>System setup> System admin>User>Set Password
3) User name and password should not exceed 12 characters and should not contain such as &*! @ (... #% and other special characters
If you can login NVR with a password, but can't login on App, please confirm that the password conforms to the format.
Note：App login username and password are different from the camera login username and password. They are two different sets of username and password system.